BackgroundBreast-fed infants grow more slowly than bottle-fed infants. This growth deceleration sometimes alarms health care personnel to the point of considering other forms of nutrition.ObjectivesTo evaluate the final adult anthropometric outcome associated with breast or formula feeding during infancy.DesignHeight and weight data were collected from eight well-baby clinics representing various ethnic origins, lifestyles, and socioeconomic backgrounds. Children were measured every 1 to 2 months for the first 6 months, every 3 months until 2 years of age, and yearly thereafter, until they reached their final height. Longitudinal data were collected from 1960 healthy children (961 boys). Overall, 613 of the children were breast fed for 1 year and 218 for 6 months.ResultsThe magnitude of the decline in Z scores of breast-fed vs. bottle-fed infants, between birth and 1 year of age was not as great for height as for weight −0.2 and −0.3 respectively, and disappeared at 2 years of age. The weight for height decreased between birth and the end of the first year in breast-fed children by 0.3 (Z score). Children switched to bottle feeding exhibited a growth spurt. However, there was no difference in the final heights or weights of breast-fed children compared with bottle-fed children 165.3 ± 6.2 (n = 134) versus 164.9 ± 6.4 (n = 195) in females, respectively, and 175.3 ± 6.8 (n = 122) versus 175.8 ± 7.1 (n = 162) in males, respectively. Adult obesity in this sample population (n = 637) was correlated with maternal obesity. Maternal BMI SD correlated with offspring BMI SD at 18 years of age (r = 0.873,P< 0.001) but not with breast feeding. Adult BMI was similar between the breast-fed and bottle-fed groups.ConclusionsDespite their slower growth rate, breast-fed children reach the same final height as bottle-fed children. Breast-fed infants should be monitored according to specifically designed growth charts. Obesity in adult life is correlated with factors not related to breast feeding.